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27 August 2026

Mould on window frames and sills: the condensation fix

Quick answer

Mould on window frames and sills is caused by condensation — warm indoor air meeting cold glass and frames, leaving water that feeds mould. Reduce indoor humidity, wipe down condensation, improve ventilation, and treat affected frames and seals.

Why windows attract mould

Glass and frames are among the coldest surfaces in any room, so they're the first place warm, humid indoor air condenses. That pooling water on the sill and around the frame is exactly what mould needs. In Cyprus it's especially common in winter and in sealed modern apartments.

The condensation cause

Keep mould from coming back

A monthly plan from €45, or book a one-off inspection.

This is textbook condensation mould. The more moisture in your indoor air — from cooking, showering, drying laundry, breathing — the more condenses on cold windows. If you wake to wet windows most mornings, that's your sign.

How to stop it

Wipe down morning condensation before it feeds mould, ventilate the room daily, reduce indoor humidity (a dehumidifier helps), and avoid drying clothes near windows. Trickle vents and running an extractor in wet rooms reduce the moisture load across the whole home — the root of the issue is ventilation.

Treating what's there

Clean and treat mouldy frames, seals and sills. If mould has got into the wall around the reveal, or keeps returning despite better habits, it's worth an mould inspection to check the wall isn't damp. mould treatment clears established growth.

Windows mouldy every winter? book a €75 inspection or call +357 96 738151.

Frequently asked questions

Why do my windows get mould in winter?
Cold glass and frames cause warm indoor air to condense, leaving water that feeds mould. Winter makes surfaces colder, so it's worse.
How do I stop condensation on my windows?
Reduce indoor humidity, ventilate daily, wipe down morning condensation, avoid drying laundry indoors, and use trickle vents or a dehumidifier.
Is window mould harmful?
It's usually surface condensation mould that's treatable, but it can spread to walls and affect allergies, so deal with it and the underlying humidity.
Why does mould keep coming back on my window sills?
Because the condensation causing it keeps returning. Until you reduce indoor humidity and improve ventilation, the mould will regrow.

Keep mould from coming back

A monthly plan from €45, or book a one-off inspection.

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